CN108476096B

CN108476096B - Downlink transmission method, base station and terminal

Info

Publication number: CN108476096B
Application number: CN201580085618.5A
Authority: CN
Inventors: 唐浩; 魏冬冬; 周国华
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2015-12-30
Filing date: 2015-12-30
Publication date: 2020-07-21
Anticipated expiration: 2035-12-30
Also published as: JP6668482B2; WO2017113187A1; US10560227B2; EP3386136A4; EP3386136A1; JP2019502321A; US20180309546A1; EP3386136B1; CN108476096A

Abstract

A downlink transmission method, a corresponding base station and a terminal are provided to improve the receiving performance of the terminal. In some possible embodiments, a base station sends downlink control information to a terminal in a subframe n + k, where the downlink control information includes indication information and an HARQ process identifier, the indication information is used to indicate a position of at least one OFDM symbol in data sent by the base station to the terminal in the subframe n, the HARQ process identifier in the downlink control information is the same as the HARQ process identifier in the subframe n, and n is a natural number; and the base station at least transmits data which is sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information in a subframe n + k.

Description

Downlink transmission method, base station and terminal

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a downlink transmission method, a base station, and a terminal.

Background

Among the various services of today's mobile networks, video services occupy a significant portion of the network traffic. The pause phenomenon in video playing seriously affects the user experience of the mobile video service. With the introduction of new video services, such as virtual reality, video services require more bandwidth and have lower latency requirements.

L TE/L TE-a (L TE is english abbreviation of long Term Evolution (L ong Term Evolution), L TE-a is english abbreviation of L TE subsequent Evolution (L ong Term Evolution Advanced)), with 1ms as a unit (i.e. 1TTI is 1ms, TTI is Transmission Time Interval (Transmission Time Interval)), a terminal (UE) is allocated a Physical Resource Block (PRB), and a base station (NodeB) sends a data packet to a round trip Time of receiving UE feedback and receiving correct reception is 8 ms.

In order to reduce the round-trip delay of data packet transmission, a short TTI (short TTI) needs to be introduced, such as 0.5ms-TTI, 1-symbol-TTI, for example, 1-symbol-TTI, where the round-trip delay of transmission of one data packet is 8 symbols, i.e., a delay less than 1 ms. By introducing short TTI, transmission delay can be reduced, thereby ensuring the low delay requirement of video service.

Video services not only require low latency, but also transmit large packets of data, and therefore require high bandwidth requirements. For a scenario where a new UE supporting 1-symbol-TTI and a legacy (legacy) UE coexist, when legacy UE occupies more frequency domain resources in 1ms, if there is a bursty short-delay video service in the 1ms, the time-frequency resources that the new UE can use are less, resulting in an increase in delay.

In Downlink (full English name: Downlink, short English name: D L), in order to ensure the high bandwidth and low delay requirements of the short delay video service, one method is that the short delay service seizes the frequency domain resources on part of the symbols of the legacy UE, when the short delay service bursts within 1ms, the base station seizes the Resource units (full English name: Resource Element, short English name: RE), and transmits the data of the short delay service on the RE used by the legacy UE.

The method has the advantages that the high-bandwidth low-delay requirement of the short-delay service can be ensured, however, the method can cause the legacy UE to receive the legacy UE incorrectly, because the data on part of symbols of the legacy UE are not the data required by the legacy UE, and the combining gain can be reduced when the Hybrid Automatic Repeat Request (Hybrid Automatic Repeat Request, HARQ for short) is combined. And after the legacy UE receives the error and feeds back the error to the base station, the base station retransmits the data after 8 subframes, that is, the retransmission delay is longer to reach the length of 8 subframes.

Therefore, when new UEs and legacy UEs supporting short TTIs such as 1-symbol-TTI coexist, how to ensure the receiving performance of legacy UEs after the base station preempts the REs of legacy UEs for the new UEs is a technical problem that needs to be solved urgently.

Disclosure of Invention

The embodiment of the invention provides a downlink transmission method, a base station and a terminal, which are used for improving the receiving performance of the terminal.

A first aspect of the present invention provides a downlink transmission method, including: a base station may send downlink control information including indication information and a hybrid automatic repeat request (HARQ) process identifier to a terminal in a subframe n + k, where the indication information is used to indicate a position of at least one Orthogonal Frequency Division Multiplexing (OFDM) symbol in data information sent by the base station to the terminal in the subframe n, the HARQ process identifier in the downlink control information is the same as the HARQ process identifier of the subframe n, n and k are natural numbers, and k is a natural number not greater than 8; the indication information can be used by the terminal to perform corresponding operations, for example, discarding the data on the at least one OFDM symbol indicated by the indication information in the data received in the subframe n, so as to avoid reception errors and improve the reception performance; and the base station retransmits part of or all data of the subframe n to the terminal in the subframe n + k, the retransmitted data comprises data which is transmitted to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information, so that the terminal can obtain the data which cannot be received in the subframe n from the subframe n + k, the terminal is ensured to correctly receive the data, the retransmission time delay is the length of k subframes, the retransmission time delay is reduced, and the terminal can jointly decode the data received by the subframe n and the subframe n + k, thereby being beneficial to further improving the receiving performance.

The method for retransmitting data in subframe n + k by the base station may include, but is not limited to, the following three methods:

the first mode is as follows: and retransmitting all data of the subframe n to the terminal in the subframe n + k. The method retransmits all data of the subframe n, so that the success rate of combining, demodulating and decoding is higher.

The second way is: and in a subframe n + k, carrying the modulated and coded data which is sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information in at least one resource block for retransmission to the terminal. In this way, other RBs of the subframe n + k, which are not used for retransmitting the target data, may be allocated to other UEs for use, so that the utilization efficiency of the subframe n + k may be improved.

The third mode is as follows: and in a subframe n + k, retransmitting the data which is sent to the terminal and subjected to modulation coding on the at least one OFDM symbol in the subframe n indicated by the indication information and is carried in the at least one OFDM symbol to the terminal. In this way, the same number of OFDM symbols are used for retransmitting data in subframe n + k, so that the terminal can receive and decode more easily.

The implementation manner of the indication information may include, but is not limited to, the following:

in one mode, the indication information may be information in a bitmap (bitmap) format, and the indication information may include a plurality of data bits, and a value (value is 1 or 0) of the data bits is used to indicate whether a corresponding OFDM symbol is preempted. For example, each bit in the indication information may correspond to 1 OFDM symbol used to transmit data, or each bit in the indication information corresponds to 1 group of OFDM symbols used to transmit data, where the 1 group of OFDM symbols includes at least two consecutive OFDM symbols; or, each bit in the indication information corresponds to two OFDM symbols used for transmitting data, where the two OFDM symbols are two OFDM symbols with the same sequence number in two slots of the subframe n. In the method, bitmap information is used for indicating, only a plurality of data bits are needed, and the occupied transmission load is less.

In another mode, the indication information may not be information in a bitmap (bitmap) format, but may include certain indication data information, for example, including a start position of a plurality of consecutive OFDM symbols used for transmitting data, and an end position or a length of the plurality of consecutive OFDM symbols. This approach requires that the indicated OFDM symbols must be contiguous when there are multiple.

After the subframe n + k retransmits part or all of the data of the subframe n, the base station can also receive feedback information which is fed back by the terminal according to the timing relation of the subframe n + k and aims at the subframe n and the subframe n + k, wherein the feedback information is acknowledgement information ACK or negative acknowledgement information NACK. The terminal may not need to send feedback information for subframe n, but only feed back the feedback information once for subframe n and subframe n + k, which reduces the number of feedback times.

A second aspect of the present invention provides a downlink transmission method, including: corresponding to the downlink transmission method executed by the base station side in the first aspect of the present invention, the terminal may receive downlink control information that is sent by the base station in a subframe n + k and includes indication information and an HARQ process identifier, where n and k are both natural numbers, where the indication information is used to indicate a position of at least one OFDM symbol in data sent by the base station to the terminal in the subframe n, and the HARQ process identifier in the downlink control information is the same as the HARQ process identifier in the subframe n; the terminal may perform corresponding operations according to the indication information, for example, discard data on at least one OFDM symbol indicated by the indication information in the data received in the subframe n, thereby avoiding a reception error and improving reception performance; the terminal also receives data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information transmitted by the base station in the subframe n + k, so that the terminal is ensured to correctly receive the data, the retransmission time delay is the length of k subframes, and the retransmission time delay is reduced; then, the terminal may jointly decode the data received in subframe n and subframe n + k to further improve the reception performance.

The terminal may receive data retransmitted by the base station in the subframe n + k by multiple manners, where the retransmission manners include, but are not limited to, the three manners described in the first aspect of the present invention.

The implementation manner of the indication information may include, but is not limited to, several manners described in the first aspect of the present invention.

After receiving the data of the subframe n + k, the terminal may feed back the feedback information for the subframe n and the subframe n + k according to the timing relationship of the subframe n + k, that is, the feedback information is fed back only once for the subframe n and the subframe n + k, thereby reducing the feedback times.

A third aspect of the present invention provides a base station, which corresponds to the downlink transmission method of the first aspect of the present invention, and is configured to implement the downlink transmission method and achieve corresponding technical effects. The base station may include: the base station comprises a sending module and a transmission module, wherein the sending module can send downlink control information comprising indication information and HARQ (hybrid automatic repeat request) process identification to a terminal in a subframe n + k, the indication information is used for indicating the position of at least one Orthogonal Frequency Division Multiplexing (OFDM) symbol in data sent to the terminal by the base station in the subframe n, the HARQ process identification in the downlink control information is the same as the HARQ process identification of the subframe n, and n and k are both natural numbers; the transmission module may transmit at least data transmitted to the terminal on the at least one OFDM symbol in subframe n indicated by the indication information in subframe n + k. The indication information can be used by the terminal to perform corresponding operations, for example, discarding the data on the at least one OFDM symbol indicated by the indication information in the data received in the subframe n, so as to avoid reception errors and improve the reception performance; and the base station retransmits part of or all data of the subframe n to the terminal in the subframe n + k, the retransmitted data comprises data which is transmitted to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information, so that the terminal can obtain the data which cannot be received in the subframe n from the subframe n + k, the terminal is ensured to correctly receive the data, the retransmission time delay is the length of k subframes, the retransmission time delay is reduced, and the terminal can jointly decode the data received by the subframe n and the subframe n + k, thereby being beneficial to further improving the receiving performance.

The base station may retransmit data to the terminal in the subframe n + k in multiple manners, which includes but is not limited to the three manners described in the first aspect of the present invention.

The base station can receive feedback information which is fed back by the terminal according to the timing relation of the subframe n + k and simultaneously aims at the subframe n and the subframe n + k, and the feedback times are reduced.

A fourth aspect of the present invention provides a terminal, which corresponds to the downlink transmission method of the first aspect of the present invention, and is configured to implement the downlink transmission method and achieve corresponding technical effects. The terminal can comprise an information receiving module, a data processing module and a decoding module; the information receiving module can receive downlink control information which is sent by a base station in a subframe n + k and comprises indication information and an HARQ process identifier, wherein both n and k are natural numbers, the indication information is used for indicating the position of at least one Orthogonal Frequency Division Multiplexing (OFDM) symbol in data sent by the base station to the terminal in the subframe n, and the HARQ process identifier in the downlink control information is the same as the HARQ process identifier in the subframe n; the data processing module may perform corresponding operations according to the indication information, for example, discard data on at least one OFDM symbol indicated by the indication information in the data received in the subframe n, so as to avoid a reception error and improve reception performance; the data receiving module can receive the data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information transmitted by the base station in the subframe n + k, so that the correct receiving of the terminal is ensured, the retransmission time delay is the length of k subframes, and the retransmission time delay is reduced; the decoding module may jointly decode the data received in the subframe n and the subframe n + k to further improve the reception performance.

After receiving the data of the subframe n + k, the terminal may feed back feedback information simultaneously for the subframe n and the subframe n + k according to the timing relationship of the subframe n + k, thereby reducing the number of feedback times.

A fifth aspect of the present invention provides a base station, which corresponds to the downlink transmission method of the first aspect of the present invention, and is configured to implement the downlink transmission method and achieve corresponding technical effects. The base station may include: a transmitter; the transmitter may send downlink control information including indication information and an HARQ process identifier to a terminal in a subframe n + k, where the indication information is used to indicate a position of at least one orthogonal frequency division multiplexing, OFDM, symbol in data sent by the base station to the terminal in the subframe n, the HARQ process identifier in the downlink control information is the same as the HARQ process identifier in the subframe n, and n and k are both natural numbers; the transmitter may further transmit data transmitted to the terminal on at least the at least one OFDM symbol in subframe n indicated by the indication information in subframe n + k. The indication information can be used by the terminal to perform corresponding operations, for example, discarding the data on the at least one OFDM symbol indicated by the indication information in the data received in the subframe n, so as to avoid reception errors and improve the reception performance; and the base station retransmits part of or all data of the subframe n to the terminal in the subframe n + k, the retransmitted data comprises data which is transmitted to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information, so that the terminal can obtain the data which cannot be received in the subframe n from the subframe n + k, the terminal is ensured to correctly receive the data, the retransmission time delay is the length of k subframes, the retransmission time delay is reduced, and the terminal can jointly decode the data received by the subframe n and the subframe n + k, thereby being beneficial to further improving the receiving performance.

the first mode is as follows: and the transmitter retransmits all the data of the subframe n to the terminal in the subframe n + k. The method retransmits all data of the subframe n, so that the success rate of combining, demodulating and decoding is higher.

The second way is: and the transmitter retransmits the data which is sent to the terminal and subjected to modulation coding on the at least one OFDM symbol in the subframe n indicated by the indication information to the terminal in at least one resource block in a subframe n + k. In this way, other RBs of the subframe n + k, which are not used for retransmitting the target data, may be allocated to other UEs for use, so that the utilization efficiency of the subframe n + k may be improved.

The third mode is as follows: and the transmitter retransmits the data which is sent to the terminal and subjected to modulation coding on the at least one OFDM symbol in the subframe n indicated by the indication information to the terminal in at least one OFDM symbol in a subframe n + k. In this way, the same number of OFDM symbols are used for retransmitting data in subframe n + k, so that the terminal can receive and decode more easily.

The base station may further include a receiver, and the receiver may receive feedback information for the subframe n and the subframe n + k, which is fed back by the terminal according to the timing relationship of the subframe n + k. In this way, the terminal may not need to send feedback information for subframe n, but only feed back feedback information once for subframe n and subframe n + k, thereby reducing the number of feedback times.

The base station may further include a processor, where the processor may preempt at least one OFDM symbol of the terminal in subframe n, and the indication information is specifically used to indicate a position of the preempted at least one OFDM symbol.

A sixth aspect of the present invention provides a terminal, where the base station corresponds to the downlink transmission method in the fourth aspect of the present invention, and is configured to implement the downlink transmission method and obtain a corresponding technical effect. The terminal may include a receiver and a processor; corresponding to the base station in the fifth aspect of the present invention, a receiver of a terminal may receive downlink control information that is sent by the base station in a subframe n + k and includes indication information and an HARQ process identifier, where n and k are both natural numbers, the indication information is used to indicate a position of at least one orthogonal frequency division multiplexing, OFDM, symbol in data sent by the base station to the terminal in the subframe n, and the HARQ process identifier in the downlink control information is the same as the HARQ process identifier in the subframe n; the receiver may also perform corresponding operations according to the indication information, for example, discard data on at least one OFDM symbol indicated by the indication information in the data received in the subframe n, so as to avoid reception errors and improve reception performance; the receiver can also receive data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information transmitted by the base station in the subframe n + k, so that the terminal is ensured to correctly receive the data, and the retransmission delay is the length of k subframes, so that the retransmission delay is reduced; the processor may jointly decode the data received in sub-frame n and sub-frame n + k to further improve reception performance.

The terminal may receive data retransmitted by the base station in the subframe n + k by multiple manners, where the retransmission manners include, but are not limited to, the three manners described in the fifth aspect of the present invention.

The implementation manner of the indication information may include, but is not limited to, several manners described in the fifth aspect of the present invention.

The terminal may include a transmitter, and the transmitter may feed back feedback information for the subframe n and the subframe n + k according to the timing relationship of the subframe n + k, that is, the feedback information is fed back only once for the subframe n and the subframe n + k, so that the feedback frequency is reduced.

As can be seen from the above, in some possible embodiments of the present invention, the base station sends the indication information to the terminal in the subframe n + k, and may instruct the terminal to perform corresponding operations according to the indication information, for example, discard the data received on the indicated at least one OFDM symbol in the subframe n, and retransmit the data to the terminal in the subframe n + k, thereby ensuring correct reception by the terminal, reducing retransmission delay, and improving reception performance of the terminal.

Drawings

Fig. 1 is a schematic architecture diagram of a communication system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of L TE/L TE-A downlink resource mapping;

FIG. 3 is a diagram illustrating mapping of pilot signals in RBs;

fig. 4 is a diagram of a conventional downlink HARQ;

fig. 5 is a flowchart illustrating a downlink transmission method according to an embodiment of the present invention;

fig. 6 is a schematic diagram of downlink resource mapping in a retransmission method of the present invention;

fig. 7 is a schematic diagram of downlink resource mapping in a retransmission method two according to the present invention;

fig. 8 is a schematic diagram of downlink resource mapping in a retransmission mode three of the present invention;

fig. 9 is a schematic structural diagram of a base station according to an embodiment of the present invention;

fig. 10 is a schematic structural diagram of a terminal according to an embodiment of the present invention;

fig. 11 is a schematic structural diagram of a base station according to another embodiment of the present invention;

fig. 12 is a schematic structural diagram of a terminal according to another embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terms "first," "second," "third," and the like in the description and in the claims, and in the above-described drawings, are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Although L TE is taken as an example in the background section, it should be understood by those skilled in the art that the present invention is not limited to L TE but can be applied to other wireless Communication systems, such as Global System for Mobile Communication (GSM), Mobile Communication System (UMTS), Code Division Multiple Access (CDMA), new network System, etc. L TE is taken as an example to describe the specific embodiment.

The terminal related to the embodiment of the invention can comprise user equipment, can be equipment for providing voice and/or data connectivity for users, handheld equipment with a wireless connection function and the like. The terminal may be, for example, a mobile terminal such as a mobile telephone (or "cellular" telephone), or a computer having a mobile terminal such as a portable, pocket, hand-held, computer-included, or vehicle-mounted mobile device. The terminal may be connected to a Radio Access Network (RAN) via a base station (eNB) to communicate with at least one core network.

The base station (eNB) according to the embodiments of the present invention may refer to a mobile communication base station, which is a form of a radio station and refers to a radio transceiver station that performs information transfer with a terminal through a mobile communication switching center in a certain radio coverage area. For example, macro base stations, micro base stations, pico base stations, distributed base stations, etc.

Referring to fig. 1, which is a schematic diagram of an architecture of a communication system according to an embodiment of the present invention, the communication system 100 may include: a base station 110, and a terminal 120.

Next, the downstream transmission technique of L TE/L TE-A will be described first.

First, L TE/L TE-A downlink resource mapping

L TE/L TE-A adopts Orthogonal Frequency Division Multiple Access (OFDMA), which is the evolution of OFDM (Orthogonal Frequency Division Multiplexing) technology and is the combination of OFDM and FDMA (FDMA).

In time domain, a radio frame length is 10ms, which includes 10 subframes, each subframe includes 1ms, each subframe includes 2 slots (slots), each slot includes 7 (normal CP) or 6 (extended CP) OFDM symbols, please refer to fig. 2, in frequency domain, a Resource Block (full english name: Resource Block, RB for short) is formed by a plurality of subcarriers, one subcarrier under one OFDM symbol is called a Resource unit (RE), RB is the minimum unit of L TE/L TE-a downlink Resource allocation, 12 consecutive subcarriers and 1 slot form a RB. Resource Block divided into a Physical Resource Block (PRB) and a Virtual Resource Block (full name: Virtual Resource Block, full name: VRB, which refers to the actual frequency position of the Resource Block, and the PRB numbering from small to large is a form of renumbering, VRB may be mapped to the base station in various ways, and the base station may allocate the Resource in units of two slots (i.e., PRB) on 1 subframe.

Referring to fig. 3, a part of REs in a RB may be used as pilots, such as a Cell-specific Reference Signal (CRS), a user-specific Reference Signal (UE-specific RS), a Channel State measurement Reference Signal (CSI-RS), and so on.

Second, HARQ process

L TE employs HARQ protocol for retransmission, which uses stop-and-wait protocol (stop-and-wait protocol) to transmit data.

In the stop-wait protocol, after a transmitting end sends a Transport Block (TB for short), the transmitting end stops waiting for feedback information, where the feedback information includes ACK (Acknowledgement) or NACK (Negative Acknowledgement). The receiving end feeds back ACK or NACK to the TB using 1-bit information.

As shown in fig. 4, the base station eNB performs downlink data transmission in subframe 0 (or subframe n, n is a natural number), the terminal performs ACK/NACK feedback in subframe 4 (or subframe n +4), and feeds back ACK if data is correctly decoded, or feeds back NACK if data is not correctly decoded, and the eNB performs data retransmission in subframe 8 (or subframe n +8) if NACK is received.

L TE uses 8 parallel stop-and-wait processes, or 8 HARQ processes, so that when one HARQ process waits for feedback Information, the sender can use another HARQ process to continue sending data.

When the base station uses a certain HARQ process to send downlink data in the subframe n and receives NACK feedback, the base station retransmits data in the subframe n +8 using the same HARQ process, and the terminal may perform joint decoding, called HARQ combining, on the received subframe n and subframe n +8, where HARQ may be joint decoding on two subframes or more subframes.

The embodiment of the invention provides a downlink transmission method, a base station and a terminal. The following are detailed descriptions of the respective embodiments.

(example one)

Referring to fig. 5, an embodiment of the present invention provides a downlink transmission method, which includes:

501. the method comprises the steps that a base station sends downlink control information to a terminal in a subframe n + k, the downlink control information comprises indication information and hybrid automatic repeat request (HARQ) process Identification (ID), the indication information is used for indicating the position of at least one OFDM symbol in data information sent to the terminal by the base station in the subframe n, the HARQ process ID in the downlink control information is the same as the HARQ process ID of the subframe n, and n and k are natural numbers.

In this step, the base station indicates the terminal by using the indication information in the downlink control information in the subframe n + k to notify the terminal of the position of at least one OFDM symbol in the subframe n, so that the terminal can perform corresponding operations according to the indication information, for example, assuming that the position of at least one OFDM symbol indicated by the indication information is error data in the data received by the terminal in the subframe n, the terminal can discard the error information according to the indication information.

In some embodiments, the at least one OFDM symbol indicated by the indication information may be a preempted OFDM symbol. In a scenario where multiple terminals with different time lengths as TTIs coexist, for example, a scenario where a terminal adopting a 1ms TTI and a terminal adopting a p-symbol TTI coexist, a p natural number indicates 1 or more OFDM symbols; in subframe n, when the terminal using the shorter TTI has a prominent short delay service, the base station may preempt at least one OFDM symbol of the terminal using the longer TTI. Taking 3 RBs allocated to the preempted terminal as an example, 36 subcarriers are included in the frequency domain, and preempting one OFDM symbol means preempting 36 REs. Since data not belonging to the terminal is transmitted on the preempted OFDM symbol, the terminal may receive an error, and the data on the preempted OFDM symbol may be discarded. It should be noted that, in some other embodiments, the base station may also instruct the terminal to discard data on at least one OFDM symbol of the subframe n by using the indication information for other reasons.

Optionally, in some embodiments of the present invention, the downlink control information may be expanded, a field is added to the downlink control information, and the field is used to carry the indication information. For example, the indication information may be carried in an extension field of the downlink control information of the subframe n + k. The indication is performed by expanding the downlink control information, which is an easy-to-implement mode, is relatively easy to be applied to the existing communication network, and can implement dynamic indication. In other embodiments, it is also contemplated to use higher layer signaling to carry the indication information.

502. And the base station at least transmits data which is sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information in a subframe n + k.

Or, the base station retransmits part or all of data of a subframe n to the terminal in a subframe n + k, where the retransmitted data includes target data, and the target data is data sent to the terminal on at least one OFDM symbol in the subframe n indicated by the indication information.

It is easy to understand that, on at least one OFDM symbol of the subframe n indicated by the indication information, actually transmitted data is not data of the terminal, but the base station should transmit data (i.e. target data) to the terminal on at least one OFDM symbol of the subframe n indicated by the indication information, and the data cannot be transmitted due to preemption or the like, and for this reason, the base station retransmits the target data to the terminal in the subframe n + k.

Different from the prior art that data retransmission is performed in the subframe n +8 after NACK fed back by the terminal is received, in the embodiment of the present invention, retransmission of target data is performed in the subframe n + k, so that retransmission delay can be reduced. All data of subframe n may be retransmitted or only part of the data may be retransmitted.

503. And the terminal receives downlink control information sent by the base station in a subframe n + k, wherein the downlink control information comprises indication information and a hybrid automatic repeat request (HARQ) process identifier.

504. The terminal receives data sent to the terminal on the at least one OFDM symbol in a subframe n indicated by the indication information transmitted by the base station in a subframe n + k;

that is, the terminal receives part or all of the data of the subframe n retransmitted by the base station in the subframe n + k, and the retransmitted data includes the target data.

505. And the terminal performs corresponding operation according to the indication information, for example, discarding data on at least one OFDM symbol indicated by the indication information in the data received by the subframe n.

The terminal needs to buffer the data symbol information received by the subframe n (i.e. data on a plurality of OFDM symbols received directly, not soft bit information after soft decision decoding), and can discard the data on at least one OFDM symbol indicated by the indication information in the subframe n to avoid reception errors, thereby preventing more errors and more retransmission delays caused during subsequent HARQ combining.

506. And the terminal jointly decodes the data received in the subframe n and the subframe n + k.

The terminal may perform joint decoding (e.g., soft decision decoding) on the data received in the subframe n and the subframe n + k to obtain correct data. Because the error data in the subframe n is discarded in advance, the combination gain can be improved and the combination success rate can be improved when the combined decoding and the HARQ are combined.

After receiving the subframe n and the subframe n + k, the terminal may further send feedback information to the base station, where the feedback information refers to ACK or NACK. Two feedback approaches are provided herein: one is in the same manner as the conventional feedback, and the other is to feed back feedback information for the subframe n and the subframe n + k according to the timing relationship of the subframe n + k. The following are described separately:

for FDD (Frequency Division duplex) HARQ:

one mode is that the terminal feeds back feedback information aiming at a subframe n and a subframe n + k respectively at a subframe n +4 and a subframe n + k +4 respectively; this approach is the same as the conventional feedback approach.

The other mode is as follows: feedback information for the subframe n and the subframe n + k is fed back at the subframe n + k +4, that is, feedback information is fed back only once at the subframe n + k +4 for two subframes, i.e., the subframe n and the subframe n + k. By adopting the feedback mode, the feedback times are reduced in fact, the feedback mode is simplified, and part of uplink transmission resources are released.

For TDD (Time Division duplex) HARQ:

as shown in table 1, the TDD mapping chart shows 7 mapping schemes of 0 to 6, where each mapping scheme defines the allocation of 10 subframes of 0 to 9 in a frame, where D denotes downlink, U denotes uplink, and S denotes special subframe. The terminal may perform uplink transmission in the subframe allocated as U.

TABLE 1 TDD

As shown in table 2, it is a TDD HARQ timing relationship, in TDD, a PDSCH (physical downlink Shared Channel) sent by multiple downlink subframes may need to reply ACK or nack in the same uplink subframe, if a terminal detects PDSCH transmission in downlink subframe n-Q, the terminal may feed back ACK or nack in uplink subframe n, where Q ∈ Q, for different TDD configurations, Q is as shown in the following table:

TABLE 2 TDD HARQ timing relationship

In the above table, "-" indicates that ACK or NACK is not allowed to be fed back in the subframe. Taking the proportioning mode "1" as an example, ACK or NACK feedback may be performed in

subframes

2, 3, 7, and 8, where subframe n-6 or n-7 may be fed back in subframe 2 (n represents the sequence number of subframe 2).

Two feedback approaches are provided herein for TDD HARQ:

one way is to send feedback information for subframe n and subframe n + k respectively according to the query result by querying the table 2; this approach is the same as the conventional feedback approach.

The other mode is as follows: by checking the above table 2 to confirm the timing relationship of the subframe n + k, feedback information for the subframe n and the subframe n + k is fed back at the same time in the corresponding subframe, that is, feedback information is fed back only once in both subframes, subframe n and subframe n + k. By adopting the feedback mode, the feedback times are reduced in fact, the feedback mode is simplified, and part of uplink transmission resources are released.

The base station can know whether the terminal receives the information correctly or not through feedback information which is fed back by the receiving terminal according to the timing relation of the subframe n + k and aims at the subframe n and the subframe n + k.

In the embodiment of the present invention, there may be various manners of indicating the preempted OFDM symbol by using the indication information, including but not limited to the following manners:

mode 1: the indication information is information of a bitmap file (bitmap format), each bit in the indication information corresponds to 1 OFDM symbol used for transmitting data information, and 1 or 0 represents whether the corresponding OFDM symbol is indicated, for example, 1 represents that the corresponding OFDM symbol is indicated, and 0 represents that the corresponding OFDM symbol is not indicated.

Taking the example that 1 subframe includes 14 OFDM symbols under Normal CP, when this method is indicated by bitmap, since the OFDM symbols (which can be used as pilots, for example, 3) occupied by PDCCH are not preempted, the 3 OFDM symbols may not be considered, and for the remaining 11 OFDM symbols, the bitmap indication of 11 bits (bits) is used, where each bit indicates whether one OFDM symbol is preempted, for example, 1 indicates that it is preempted, and 0 indicates that it is not preempted.

Mode 2: similar to the manner 1, the indication information is still information in bitmap format, but each bit in the indication information corresponds to 1 group of OFDM symbols used for transmitting data information, the 1 group of OFDM symbols includes at least two consecutive OFDM symbols, and 1 or 0 represents whether the corresponding group of OFDM symbols is indicated. I.e. indicated by bitmap and expressed in symbol groups, e.g.

OFDM symbols

3 and 4 are 1 group, and 1 bit indicates whether the group is preempted.

Mode 3: similar to the mode 2, the indication information is still information in a bitmap format of a bitmap file, each bit in the indication information corresponds to two OFDM symbols used for transmitting data information, but the two OFDM symbols are two OFDM symbols with the same sequence number in two slots (slots) of the subframe n. In other words, the positions of the OFDM symbols removed by two slots can be considered to be the same, indicating the bitmap of one slot.

Mode 4: the indication information includes a start position of a plurality of continuous OFDM symbols used for transmitting data information, and also includes an end position or length of the plurality of continuous OFDM symbols.

For example, the base station may be restricted to preempt only consecutive OFDM symbols, and the indication information may indicate the start position (i.e., the sequence number of the first preempted OFDM symbol) and the length (i.e., the number of consecutive preempted OFDM symbols) of the consecutive preempted OFDM symbols.

If the base station is restricted to be able to preempt 2 consecutive OFDM symbols at most, the indication information may notify the starting position (i.e., the sequence number of the first preempted OFDM symbol) and the ending position (i.e., the sequence number of the last preempted OFDM symbol) of each of the two consecutive preempted OFDM symbols, or may also notify the starting position and the length of each of the two consecutive preempted OFDM symbols.

It should be noted that k may be a natural number not greater than 8, for example, 1, 2, 3, or the like. In some embodiments, k may be equal to RTT (Round-trip time), that is, a time slot sent by the new downlink control information is the same as a time slot sent by the downlink control information retransmitted by the HARQ process, and the new downlink control information may carry retransmission information of the HARQ process. For example, when k is 8, new downlink control information (including downlink control information indicating the OFDM symbol position of the subframe n) is transmitted at n +8, the original downlink control information may not be transmitted, and the retransmission information may be included in the new downlink control information.

As can be seen from the above, in some possible embodiments of the present invention, the indication information is used to instruct the terminal to perform corresponding operations on the indicated data on the at least one OFDM symbol, for example, to instruct the terminal to discard the erroneous data received on the at least one OFDM symbol of the subframe n, so as to avoid the reception error and improve the reception performance; and retransmitting part of or all data of the subframe n in the subframe n + k, wherein the retransmitted data comprises data which is transmitted to the terminal on at least one OFDM symbol of the subframe n indicated by the indication information, so that not only is the correct receiving of the terminal ensured, but also the retransmission time delay is the length of k subframes, and the retransmission time delay is reduced. In addition, the terminal can jointly decode the data received by the subframe n and the subframe n + k, which is beneficial to further improving the receiving performance. In addition, when the joint decoding (that is, HARQ combining) is performed, since the error data in the subframe n is discarded in advance, the combining gain can be improved, and the success rate can be improved. Therefore, the success rate of correct receiving of the terminal is effectively improved, the retransmission time delay is reduced, and the receiving performance of the terminal is improved.

In the embodiment of the present invention, a plurality of retransmission modes are available for retransmitting part or all of the data of the subframe n + k, and several retransmission modes are further described below by taking an embodiment mode in a plurality of specific scenarios as an example.

The first retransmission mode:

in this embodiment, the process that the base station transmits, in the subframe n + k, at least the data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information includes: and the base station retransmits all data of the subframe n to the terminal in the subframe n + k. And, subframe n + k and subframe n use the same HARQ process ID. The following examples illustrate:

referring to fig. 6, a base station transmits downlink data of a UE1 in a subframe n, where a short delay service needs to be transmitted in the 5 th symbol of the subframe n, and the base station preempts subcarriers on OFDM symbol 5 and symbol 6 on an RB used by a UE1 to ensure the delay requirement of the short delay service.

Taking k as an example, in subframe n +1, the base station includes indication information in the downlink control information addressed to the UE1, indicating the position of the OFDM symbol in subframe n that the UE1 is preempted by the base station. Then, the base station retransmits all the data of the subframe n to the UE1 in the subframe n +1, and uses the same HARQ process ID. Since the length of a subframe is 1ms, it can be regarded that the data of the same 1ms is transmitted in the next subframe.

And the UE receives the downlink control information at the subframe n +1, and if the position of the preempted OFDM symbol on the subframe n is known, the received data on the

OFDM symbols

5 and 6 on the subframe n are removed, and then the data received by the subframe n and the subframe n +1 are merged, demodulated and decoded.

It should be noted that, before sending data to the UE, the base station needs to perform modulation coding on the original data, and map the data after modulation coding to multiple REs of the downlink data frame for downlink transmission. The UE can obtain the original information of the data after demodulating and decoding.

In this embodiment, since all data of the subframe n is retransmitted in the subframe n + k, the subframe n + k may adopt the same modulation and coding scheme as the subframe n, or may adopt a different modulation and coding scheme from the subframe n.

In this embodiment, after receiving the downlink subframe, the UE caches the original time-frequency domain information of the data, so as to be used for merging, demodulating and decoding a plurality of subframes, thereby improving the receiving performance.

In this embodiment, all data of the subframe n is retransmitted in the subframe n + k, instead of only target data, so that the success rate of combining, demodulating and decoding is higher.

And a second retransmission mode:

in this embodiment, the process that the base station transmits, in the subframe n + k, at least the data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information includes: and the base station carries the data which is sent to the terminal and subjected to modulation coding on the at least one OFDM symbol in the subframe n indicated by the indication information in at least one resource block RB in a subframe n + k for retransmission to the terminal. The following examples illustrate:

referring to fig. 7, a base station transmits downlink data of a UE1 in a subframe n, where a short delay service needs to be transmitted in the 5 th OFDM symbol of the subframe n, and the base station preempts subcarriers on OFDM symbol 5 and symbol 6 on an RB used by a UE1 to ensure the delay requirement of the short delay service.

Taking k as an example, in subframe n +1, the base station includes indication information in the downlink control information addressed to the UE1, indicating the position of the OFDM symbol in subframe n that the UE1 is preempted by the base station.

In this embodiment, the base station retransmits only the target data on the preempted OFDM symbol of the subframe n in the subframe n +1, instead of retransmitting all the data, so that the subframe n +1 needs to adopt the same modulation and coding scheme as the subframe n, that is, the target data is data that is mapped onto at least one OFDM symbol indicated by the indication information and is modulated and coded on the subframe n.

That is, subframe n +1 is to transmit the unsent data (in this embodiment, the data carried on OFDM symbol 5 and symbol 6) preempted in subframe n. And mapping data of the subframe n to the REs through modulation coding, wherein the information mapped to the OFDM symbol 5 and the symbol 6 is sent in the subframe n +1, the subframe n +1 does not need modulation coding, for example, 72 REs are preempted, and then the information of the preempted 72 REs which are not sent in the subframe n is sent in the subframe n +1 by the 72 REs. Since the length of a subframe is 1ms, it can be considered that data on the

last 1ms symbols

5 and 6 is transmitted in the next subframe.

For example, in subframe n, the base station allocates 3 RBs (36 subcarriers in the frequency domain) to the UE1, and preempts REs on OFDM symbol 5 and symbol 6, that is, 72 REs in total. In subframe n +1, the base station may use 1 RB (more than 72 data REs) to send the data modulated and encoded on the 72 REs to the UE1, where the mapping order is frequency domain first and time domain later. Optionally, the remaining unallocated idle REs may be filled with 0, or the target data of 72 REs may be copy-filled until all REs in the RB are full, so as to improve the receiving performance.

And the UE receives the downlink control information at the subframe n +1, and if the position of the preempted OFDM symbol on the subframe n is known, the UE removes the received data on the corresponding OFDM symbol received on the subframe n, and then combines, demodulates and decodes the data with the data received by the subframe n + 1. In this embodiment, after receiving the downlink subframe, the UE caches the original time-frequency domain information of the data, so as to be used for combining, demodulating and decoding a plurality of subframes, thereby improving the receiving performance.

It should be noted that, other RBs of the subframe n + k that are not used for retransmitting the target data may be allocated to other UEs for use, so as to improve the utilization efficiency of the subframe n + k.

And a third retransmission mode:

in this embodiment, the process that the base station transmits, in the subframe n +1, at least the data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information includes: and the base station retransmits the data which is sent to the terminal and subjected to modulation coding on the at least one OFDM symbol in the subframe n indicated by the indication information to the terminal in at least one OFDM symbol in a subframe n + 1. The following examples illustrate:

referring to fig. 8, a base station transmits downlink data of a terminal 1 in a subframe n, a short delay service needs to be transmitted in the 5 th symbol of the subframe n, and the base station occupies subcarriers on the symbol 5 and the symbol 6 on an RB used by the terminal 1 in order to guarantee the delay requirement of the short delay service.

Taking k as an example, in subframe n +1, the base station includes, in the downlink control information for terminal 1, indication information indicating the positions of

OFDM symbols

5 and 6 in subframe n, which are occupied by the base station for terminal 1.

Similar to scenario 2, in this embodiment, the base station retransmits, in a subframe n +1, only target data on the preempted OFDM symbol of the subframe n, instead of retransmitting all data, so that the subframe n +1 needs to adopt a modulation and coding scheme the same as that of the subframe n, that is, the target data is data, which is mapped to at least one OFDM symbol indicated by the indication information on the subframe n and is subjected to modulation and coding, and the target data is transmitted to the base station. Since the length of the subframe is 1ms, it can be regarded that at least one OFDM symbol of the next subframe transmits the last 1ms data, and only the OFDM symbol with the last 1ms preempted transmits the unsent data, and the UE still receives at 1ms tti, but only takes the data on the

symbols

5 and 6.

In this embodiment, the number of RBs used in the subframe n +1 is the same as the number of RBs in the subframe n, but the unsent target data preempted by the UE1 is transmitted only in k OFDM symbols, where k is a natural number and is equal to the number of preempted OFDM symbols in the subframe n, and the positions of the k OFDM symbols may have the following modes:

mode 1: the position of the preempted OFDM symbol of the subframe n is the same. The mode is a predefined mode, the predefined k OFDM symbol positions are the same as the preempted OFDM symbol positions on the subframe n, for example, if the

OFDM symbols

5 and 6 are preempted in the subframe n, the data which is not transmitted in the subframe n is transmitted on the

OFDM symbols

5 and 6 of the subframe n + 1.

Mode 2: and the position of the preempted OFDM symbol of the subframe n is different, and is indicated by downlink control information, and at this time, the indication information is also used for indicating the position of the OFDM symbol of the subframe n +1 used for retransmission.

The UE receives data of k OFDM symbols, which are predefined or indicated by the base station, in subframe n +1, and jointly decodes the received data in subframe n (i.e., removes the data in the preempted OFDM symbols). In this embodiment, after receiving the downlink subframe, the UE caches the original time-frequency domain information of the data, so as to be used for combining, demodulating and decoding a plurality of subframes, thereby improving the receiving performance.

In this embodiment, the same number of OFDM symbols is used to retransmit the target data, and the target data has the same carrying manner in the two subframes, which is beneficial to improving the receiving speed and the efficiency of joint decoding.

In the above, the downlink transmission method of the present invention is introduced by using several embodiments, and several retransmission methods of the method are described. By adopting multi-subframe joint transmission, the position of at least one OFDM symbol of the subframe n is indicated in the downlink control information of the subframe n +1, so that the terminal can perform corresponding operations according to the indication information, for example, data received on the indicated at least one OFDM symbol of the subframe n is abandoned, and part or all of the data of the subframe n is retransmitted in the subframe n + k, thereby ensuring that the terminal correctly receives and reduces time delay, and solving the technical problems of terminal transmission failure and time delay increase caused by short time delay preempting data RE of the terminal in the prior art.

In order to better implement the above-mentioned aspects of the embodiments of the present invention, the following also provides related devices for implementing the above-mentioned aspects cooperatively.

(example two)

Referring to fig. 9, an embodiment of the present invention provides a base station 900, which may include:

a sending module 901, configured to send downlink control information to a terminal in a subframe n + k, where the downlink control information includes indication information and a hybrid automatic repeat request HARQ process identifier, the indication information is used to indicate a position of at least one orthogonal frequency division multiplexing OFDM symbol in data sent by the base station to the terminal in the subframe n, an HARQ process identifier in the downlink control information is the same as an HARQ process identifier in the subframe n, and n and k are both natural numbers;

a transmission module 902, configured to transmit, in a subframe n + k, at least data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information.

In some embodiments, the transmission module 902 is specifically configured to retransmit all data of the subframe n to the terminal in the subframe n + k by the base station.

In some embodiments, the transmission module 902 is specifically configured to retransmit, in a subframe n + k, data carried in at least one resource block and subjected to modulation coding, sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information, to the terminal.

In some embodiments, the base station 900 further comprises:

a processing module 903, configured to fill 0 in a free resource unit of the at least one resource block.

In some embodiments, the transmission module 902 is specifically configured to retransmit, in a subframe n + k, the modulation-coded data, which is sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information and is carried in the at least one OFDM symbol, to the terminal.

In some embodiments, the OFDM symbol of the subframe n + k used for retransmission is the same as the position of the OFDM symbol indicated by the indication information; or the position of the OFDM symbol for retransmission of the subframe n + k is different from the position of the OFDM symbol indicated by the indication information, and the indication information is also used for indicating the position of the OFDM symbol for retransmission of the subframe n + k.

In some embodiments, the indication information is information in a bitmap format;

each bit in the indication information corresponds to 1 OFDM symbol used for transmitting data, and 1 or 0 is used for indicating whether the corresponding OFDM symbol is indicated;

or, each bit in the indication information corresponds to 1 group of OFDM symbols used for transmitting data, and 1 or 0 represents whether the corresponding group of OFDM symbols is indicated, where the 1 group of OFDM symbols includes at least two consecutive OFDM symbols;

or, each bit in the indication information corresponds to two OFDM symbols used for transmitting data, and 1 or 0 represents whether the corresponding two OFDM symbols are indicated, where the two OFDM symbols are two OFDM symbols with the same sequence number in two slots of the subframe n.

In some embodiments, the indication information includes a start position of a plurality of consecutive OFDM symbols used to transmit data, and also includes an end position or a length of the plurality of consecutive OFDM symbols.

In some embodiments, the base station 900 further comprises:

a scheduling module 904, configured to preempt at least one OFDM symbol of the terminal in a subframe n, where the indication information is specifically used to indicate a position of the preempted at least one OFDM symbol.

In some embodiments, the base station 900 further comprises:

a receiving module 905, configured to receive feedback information, which is fed back by the terminal according to the timing relationship of the subframe n + k and is for the subframe n and the subframe n + k, where the feedback information is acknowledgement information ACK or negative acknowledgement information NACK.

It should be noted that each functional module of the base station 900 may correspond to a specific hardware structure, for example, the transmitting module 901 and the transmitting module 902 may correspond to a transmitter, the processing module 903 and the scheduling module 904 may correspond to a processor, the receiving module 905 may correspond to a receiver, and each functional module is implemented by a respective corresponding hardware unit.

It can be understood that the functions of each functional module of the base station in the embodiment of the present invention may be specifically implemented according to the method in the foregoing method embodiment, and the specific implementation process may refer to the related description in the foregoing method embodiment, which is not described herein again.

(example III)

Referring to fig. 10, an embodiment of the present invention provides a terminal 1000, which may include:

an information receiving module 1001, configured to receive downlink control information sent by a base station in a subframe n + k, where n and k are both natural numbers, where the downlink control information includes indication information and an HARQ process identifier, where the indication information is used to indicate a position of at least one Orthogonal Frequency Division Multiplexing (OFDM) symbol in data sent by the base station to the terminal in the subframe n, and the HARQ process identifier in the downlink control information is the same as the HARQ process identifier in the subframe n;

a data receiving module 1002, configured to receive data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information transmitted by the base station in a subframe n + k;

a data processing module 1003, configured to discard, according to the indication information, data on at least one OFDM symbol indicated by the indication information in the data received in the subframe n;

a decoding module 1004, configured to jointly decode the data received in the subframe n and the subframe n + k.

In some embodiments, terminal 1000 can further include:

a feedback module 1005, configured to feed back feedback information for the subframe n and the subframe n + k according to the timing relationship of the subframe n + k, where the feedback information is acknowledgement information ACK or negative acknowledgement information NACK.

In some embodiments, the indication information is specifically configured to instruct the base station to preempt a position of at least one OFDM symbol of the terminal in subframe n.

In some embodiments, the data receiving module 1002 is specifically configured to receive all data of the subframe n retransmitted by the base station in the subframe n + k.

In some embodiments, the data receiving module 1002 is specifically configured to receive modulation-coded data, which is retransmitted by the base station in at least one resource block of a subframe n + k and sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information.

In some embodiments, the free resource elements, REs, of the at least one resource block are padded with 0.

In some embodiments, the data receiving module 1002 is specifically configured to receive modulation-coded data, which is retransmitted by the base station in at least one OFDM symbol in a subframe n + k and sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information.

In some embodiments, the indication information is information in bitmap format of a bitmap file;

each bit in the indication information corresponds to 1 OFDM symbol used for transmitting data information, and 1 or 0 is used for indicating whether the corresponding OFDM symbol is preempted or not;

or, each bit in the indication information corresponds to 1 group of OFDM symbols used for transmitting data information, and 1 or 0 represents whether the corresponding group of OFDM symbols is preempted, where the 1 group of OFDM symbols includes at least two consecutive OFDM symbols;

or, each bit in the indication information corresponds to two OFDM symbols used for transmitting data information, and 1 or 0 represents whether the corresponding two OFDM symbols are preempted, where the two OFDM symbols are two OFDM symbols with the same sequence number in two slots of the subframe n.

In some embodiments, the indication information includes a start position of a plurality of consecutive OFDM symbols used to transmit data information, and also includes an end position or length of the plurality of consecutive preempted OFDM symbols.

It should be noted that each functional module of the terminal 1000 can correspond to a specific hardware structure, for example, the information receiving module 1001 and the data receiving module 1002 can correspond to a receiver, the data processing module 1003 can correspond to a receiver or a processor, the decoding module 1004 can correspond to a processor, and the feedback module 1005 can correspond to a transmitter, where each functional module is implemented by a respective corresponding hardware unit.

(example four)

Referring to fig. 11, an embodiment of the present invention provides a base station 1100, where the base station 1100 includes:

a transmitter 1101, configured to send downlink control information to a terminal in a subframe n + k, where the downlink control information includes indication information and a hybrid automatic repeat request HARQ process identifier, the indication information is used to indicate a position of at least one orthogonal frequency division multiplexing OFDM symbol in data sent by the base station to the terminal in the subframe n, the HARQ process identifier in the downlink control information is the same as the HARQ process identifier in the subframe n, and n and k are both natural numbers;

the transmitter 1101 is further configured to transmit, in a subframe n + k, at least data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information.

In some embodiments, the transmitter 1101 is specifically configured to: and retransmitting all data of the subframe n to the terminal in the subframe n + k.

In some embodiments, the transmitter 1101 is specifically configured to: and in a subframe n + k, carrying the modulated and coded data which is sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information in at least one resource block for retransmission to the terminal.

In some embodiments, base station 1100 may also include: a processor 1102 configured to fill 0 in a free resource element, RE, of the at least one resource block.

In some embodiments, the transmitter 1101 is specifically configured to: and in a subframe n + k, retransmitting the data which is sent to the terminal and subjected to modulation coding on the at least one OFDM symbol in the subframe n indicated by the indication information and is carried in the at least one OFDM symbol to the terminal.

each bit indicated by the indication information corresponds to 1 OFDM symbol used for transmitting data information, and 1 or 0 is used for indicating whether the corresponding OFDM symbol is indicated;

or, each bit indicated by the indication information corresponds to 1 group of OFDM symbols used for transmitting data information, and 1 or 0 represents whether the corresponding group of OFDM symbols is indicated, where the 1 group of OFDM symbols includes at least two consecutive OFDM symbols;

or, each bit indicated by the indication information corresponds to two OFDM symbols used for transmitting data information, and 1 or 0 represents whether the corresponding two OFDM symbols are indicated, where the two OFDM symbols are two OFDM symbols with the same sequence number in two slots of the subframe n.

In some embodiments, the indication information includes a start position of a plurality of consecutive OFDM symbols used to transmit data information, and also includes an end position or a length of the plurality of consecutive OFDM symbols.

In some embodiments, the processor 1102 is further configured to preempt at least one OFDM symbol of the terminal in subframe n, and the indication information is specifically used to indicate a position of the preempted at least one OFDM symbol.

In some embodiments, base station 1100 may also include: a receiver 1103, configured to receive feedback information, which is fed back by the terminal according to the timing relationship of the subframe n + k and is for the subframe n and the subframe n + k, where the feedback information is acknowledgement information ACK or negative acknowledgement information NACK.

It can be understood that the functions of each module of the base station in the embodiment of the present invention may be specifically implemented according to the method in the foregoing method embodiment, and the specific implementation process may refer to the relevant description in the foregoing method embodiment, which is not described herein again.

As can be seen from the above, in some feasible embodiments of the present invention, by using multi-subframe joint transmission, the position of at least one OFDM symbol of a subframe n is indicated in the downlink control information of a subframe n + k, so that a terminal can perform corresponding operations according to the indication information, for example, discarding data received on the indicated at least one OFDM symbol of the subframe n, and retransmitting part or all of the data of the subframe n in the subframe n + k, thereby ensuring that the terminal receives the data correctly and reducing the time delay, and solving the technical problems of terminal transmission failure and time delay increase caused by short-time-delay preemption of data RE of the terminal in the prior art.

(example V)

Referring to fig. 12, an embodiment of the present invention provides a terminal 1200, which may include:

a receiver 1201, configured to receive downlink control information sent by a base station in a subframe n + k, where n and k are both natural numbers, where the downlink control information includes indication information and an HARQ process identifier, the indication information is used to indicate a position of at least one OFDM symbol in data sent by the base station to the terminal in the subframe n, and the HARQ process identifier in the downlink control information is the same as the HARQ process identifier in the subframe n;

the receiver 1201 is further configured to receive data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information transmitted by the base station in a subframe n + k;

the receiver 1201 is further configured to discard, according to the indication information, data on at least one OFDM symbol indicated by the indication information in the data received in the subframe n;

a processor 1202 configured to jointly decode data received in subframe n and subframe n + k.

In some embodiments, terminal 1200 further comprises: the transmitter 1203 is configured to feed back feedback information for the subframe n and the subframe n + k according to the timing relationship of the subframe n + k, where the feedback information is acknowledgement information ACK or negative acknowledgement information NACK.

In some embodiments, the indication information is specifically used to indicate the position of at least one OFDM symbol of the terminal occupied by the base station in subframe n.

In some embodiments, the receiver 1201 is specifically configured to: and receiving all data of the subframe n retransmitted by the base station in the subframe n + k.

In some embodiments, the receiver 1201 is specifically configured to: and receiving data which is retransmitted by the base station in at least one resource block of a subframe n + k and sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information after modulation and coding.

In some embodiments, the free resource unit padding of the at least one resource block is 0.

In some embodiments, the receiver 1201 is specifically configured to: and receiving data which is retransmitted by the base station in at least one OFDM symbol in a subframe n + k and sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information after modulation and coding.

In some embodiments, the indication information includes a start position of a plurality of consecutive OFDM symbols used to transmit data information, and also includes an end position or a length number of the plurality of consecutive OFDM symbols.

(example six)

Referring to fig. 1, an embodiment of the present invention provides a communication system 100; the communication system 100 may include a base station 110 and a terminal (terminal) 120, where the base station 110 is the base station according to the fourth embodiment of the present invention, and the terminal is the terminal according to the fifth embodiment of the present invention.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to the related descriptions of other embodiments.

It should be noted that, for simplicity of description, the above-mentioned method embodiments are described as a series of acts or combination of acts, but those skilled in the art will recognize that the present invention is not limited by the order of acts, as some steps may occur in other orders or concurrently in accordance with the invention. Further, those skilled in the art should also appreciate that the embodiments described in the specification are preferred embodiments and that the acts and modules referred to are not necessarily required by the invention.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

Those skilled in the art will appreciate that all or part of the steps in the methods of the above embodiments may be implemented by associated hardware instructed by a program, which may be stored in a computer-readable storage medium, and the storage medium may include: ROM, RAM, magnetic or optical disks, and the like.

The downlink transmission method, the base station and the terminal provided by the embodiment of the present invention are described in detail above, and a specific example is applied in the description to explain the principle and the embodiment of the present invention, and the description of the above embodiment is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A downlink transmission method, comprising:

a base station sends downlink control information to a terminal in a subframe n + k, wherein the downlink control information comprises indication information and a hybrid automatic repeat request (HARQ) process identifier, the indication information is used for indicating the position of at least one Orthogonal Frequency Division Multiplexing (OFDM) symbol which is preempted by the base station in data sent to the terminal by the subframe n, the HARQ process identifier in the downlink control information is the same as the HARQ process identifier of the subframe n, and n and k are both natural numbers;

and the base station at least transmits data which is sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information in a subframe n + k.

2. The method of claim 1, wherein the base station transmits data sent to the terminal on at least the at least one OFDM symbol in subframe n indicated by the indication information in subframe n + k, comprises:

and the base station retransmits all data of the subframe n to the terminal in the subframe n + k.

3. The method of claim 1, wherein the base station transmits data sent to the terminal on at least the at least one OFDM symbol in subframe n indicated by the indication information in subframe n + k, comprises:

and the base station retransmits the data which is sent to the terminal and subjected to modulation coding on the at least one OFDM symbol in the subframe n indicated by the indication information to the terminal in at least one resource block in a subframe n + k.

4. The method of claim 3, further comprising:

filling 0 in the free resource unit of the at least one resource block.

5. The method of claim 1, wherein the base station transmits data sent to the terminal on at least the at least one OFDM symbol in subframe n indicated by the indication information in subframe n + k, comprises:

and the base station retransmits the data which is sent to the terminal and subjected to modulation coding on the at least one OFDM symbol in the subframe n indicated by the indication information to the terminal in at least one OFDM symbol in a subframe n + k.

6. The method of claim 5,

the position of the OFDM symbol used for retransmission of the subframe n + k is the same as that of the OFDM symbol indicated by the indication information;

or the position of the OFDM symbol for retransmission of the subframe n + k is different from the position of the OFDM symbol indicated by the indication information, and the indication information is also used for indicating the position of the OFDM symbol for retransmission of the subframe n + k.

7. The method according to any one of claims 1 to 6,

the indication information is information in a bitmap format;

8. The method according to any one of claims 1 to 6,

the indication information includes a start position of a plurality of consecutive OFDM symbols used to transmit data, and also includes an end position or a length of the plurality of consecutive OFDM symbols.

9. The method according to any one of claims 1 to 6, wherein before the base station sends the downlink control information to the terminal in subframe n + k, the method further comprises:

and the base station preempts at least one OFDM symbol of the terminal in a subframe n, wherein the indication information is specifically used for indicating the position of the preempted at least one OFDM symbol.

10. The method according to any one of claims 1 to 6,

and the base station receives feedback information which is fed back by the terminal according to the timing relation of the subframe n + k and aims at the subframe n and the subframe n + k, wherein the feedback information is acknowledgement information ACK or negative acknowledgement information NACK.

11. A downlink transmission method, comprising:

a terminal receives downlink control information sent by a base station in a subframe n + k, wherein n and k are both natural numbers, the downlink control information comprises indication information and a hybrid automatic repeat request (HARQ) process identifier, the indication information is used for indicating the position of at least one Orthogonal Frequency Division Multiplexing (OFDM) symbol preempted in data sent by the base station to the terminal in the subframe n, and the HARQ process identifier in the downlink control information is the same as the HARQ process identifier in the subframe n;

the terminal receives data sent to the terminal on the at least one OFDM symbol in a subframe n indicated by the indication information transmitted by the base station in a subframe n + k;

the terminal discards data on at least one OFDM symbol indicated by the indication information in the data received by the subframe n according to the indication information;

and the terminal jointly decodes the data received in the subframe n and the subframe n + k.

12. The method of claim 11, further comprising:

and the terminal feeds back feedback information aiming at the subframe n and the subframe n + k according to the timing relation of the subframe n + k, wherein the feedback information is acknowledgement information ACK or negative acknowledgement information NACK.

13. The method of claim 11,

the indication information is specifically used for indicating the base station to preempt the position of at least one OFDM symbol of the terminal in a subframe n.

14. The method according to any of claims 11 to 13, wherein the receiving data sent by the base station to the terminal on the at least one OFDM symbol in subframe n indicated by the indication information transmitted in subframe n + k comprises:

and the terminal receives all data of the subframe n retransmitted by the base station in the subframe n + k.

15. The method according to any of claims 11 to 13, wherein the receiving data sent by the base station to the terminal on the at least one OFDM symbol in subframe n indicated by the indication information transmitted in subframe n + k comprises:

and the terminal receives the data which is retransmitted by the base station in at least one resource block of a subframe n + k and sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information, and is subjected to modulation coding.

16. The method of claim 15,

the idle resource unit padding of the at least one resource block is 0.

17. The method according to any of claims 11 to 13, wherein the receiving data sent by the base station to the terminal on the at least one OFDM symbol in subframe n indicated by the indication information transmitted in subframe n + k comprises:

and the terminal receives the data which is retransmitted by the base station in at least one OFDM symbol in the subframe n + k and sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information after modulation and coding.

18. The method of claim 17,

19. The method according to any one of claims 11 to 13,

the indication information is information in bitmap format of a bitmap file;

20. The method according to any one of claims 11 to 13,

the indication information comprises the starting position of a plurality of continuous OFDM symbols used for transmitting data information, and also comprises the ending position or the length of the plurality of continuous preempted OFDM symbols.

21. A base station, comprising:

a sending module, configured to send downlink control information to a terminal in a subframe n + k, where the downlink control information includes indication information and a hybrid automatic repeat request HARQ process identifier, the indication information is used to indicate a position of at least one orthogonal frequency division multiplexing OFDM symbol that is preempted by the base station in data sent to the terminal by the subframe n, the HARQ process identifier in the downlink control information is the same as the HARQ process identifier of the subframe n, and n and k are both natural numbers;

and a transmission module, configured to transmit, in a subframe n + k, at least data sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information.

22. The base station of claim 21,

the transmission module is specifically configured to retransmit all data of the subframe n to the terminal in the subframe n + k by the base station.

23. The base station of claim 21,

the transmission module is specifically configured to, in a subframe n + k, carry, in at least one resource block, data that is sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information and that is subjected to modulation coding, and retransmit the data to the terminal.

24. The base station of claim 23, further comprising:

a processing module, configured to fill 0 in an idle resource unit of the at least one resource block.

25. The base station of claim 21,

the transmission module is specifically configured to, in a subframe n + k, carry, in at least one OFDM symbol, data that is sent to the terminal on the at least one OFDM symbol in the subframe n indicated by the indication information and that is subjected to modulation coding, and retransmit the data to the terminal.

26. The base station of claim 25,

27. The base station according to any of the claims 21 to 26,

the indication information is information in a bitmap format;

28. The base station according to any of the claims 21 to 26,

29. The base station according to any of claims 21 to 26, further comprising:

and a scheduling module, configured to preempt at least one OFDM symbol of the terminal in a subframe n, where the indication information is specifically used to indicate a position of the preempted at least one OFDM symbol.

30. The base station according to any of claims 21 to 26, further comprising:

and the receiving module is used for receiving feedback information which is fed back by the terminal according to the timing relation of the subframe n + k and aims at the subframe n and the subframe n + k, wherein the feedback information is acknowledgement information ACK or negative acknowledgement information NACK.

31. A terminal, characterized in that it is adapted to implement the method according to any of claims 11-20.

32. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the method according to any one of claims 1 to 10.

33. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the method according to any one of claims 11 to 20.